How it works...

The core concepts of this recipe are enclosed in the DBGrid1TitleClick and CustomerInfoClick functions.

In the first procedure, we used the IndexFieldNames property to generate a temporary index to perform sorting based on a field related to the DBGrid column clicked, and also applying a graphical change to the column to better understand the ordering.

A temporary index accepts more than one field, so if you want to sort data by several fields you can do it by separating fields, with a semicolon.
In addition, you can also specify the sort order, such as ascending or descending, adding the suffixes  :A for ascending and :D for descending.

In the second procedure, we used Aggregate to report some customer info:

  • Total Value: This represents the total amount of all orders
  • Max Value: This represents the order with the maximum amount
  • Last Order: This represents the last date order

Aggregate are created in the CreateAggregates procedure. Here is some more information about the properties used:

  • Expression property: This defines the expression to be used to calculate the aggregate.
    • GroupingLevel property: This defines the number of indexed fields to use for grouping. By default, its value is set to 0 (no fields and no grouping; all records in a dataset).
  • IndexName property: This defines the name of the index to use for grouping. If none is specified, it will use the IndexName property of DataSet.
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